Induction rotor



Aug. 1, 1950 R. G. LE TOURNEAU INDUCTION ROTOR Filed 00T.. 27, 1947 INVENTOR R. G. .Le Touzn eauJ MLM/ulb ATTORNEYS Patented ug. l, 1.95

INDUCTION ROTOR Robert G. Le Tourneau, Longview, Tex., assignor to R. G. Le Tourneau, Inc., Stockton, Calif., a

corporation Application October 27, 1947, Serial No. 782,380

Claims. (C1. 172-120) This invention is directed to, and it is an object to` provide a novel rotor for an A. C. induction motor of high torque type; the feature of such rotor being the design thereof for the effective and accelerated dissipation of the heat from the current induced in the conductor bars.

Another object of the present invention is to provide an induction rotor, as above, wherein the heat dissipating means includes a novel resistance end bell on one end of the rotor in electrical connection with the conductor bars; such end bell being of stainless steel and thus ycapable of withstanding high heat, without damage or scaling, when the motor is operated much below synchronous speed.

An additional object of the invention is to provide an induction rotor which can be run safely at high speed; the parts being formed and assembled in a manner to prevent impairment by centrifugal force.

A further object of the invention is to produce a practical and rugged induction rotor and one which will be exceedingly eifective for the purpose for which it is designed.

These objects are accomplished by means of such structure and relative arrangement of parts as will fully appear by a perusal of the following specication and claims.

In the drawings: v

Figure 1 is a sectional elevation of the induction rotor.

Figure 2 is an enlarged fragmentary elevation of said induction rotor.

Figure 3 is a perspective view of one of the conductor bar units, detached.

Referring now more particularly to the characters of reference on the drawings, the induction rotor is formed on the motor shaft I of an A. C. induction motor of high torque type. The shaft I is reduced in diameter in part to form a radical shoulder 2 thereon and a laminated rotor 3 is engaged on the shaft in abutting relation at one end against such radial shoulder. The rotor il is maintained against relative rotation on the shaft I by means of a longitudinal key 4. f. Beyond the end of the laminated rotor 3, op posite the radial shoulder 2, the shaft supports a resistance end bell 5 of stainless steel disposed concentric to said shaft. The bell includes an elongated hub 5 and an inner end wall 'I.

The hub 6 is retained against relative rotation onthe shaft I by an extended end portion of the key 4; the inner end wall 1 of the resistance end bell bearing directly against the adjacent end of the laminated rotor 3.

Longitudinal displacement of the rotor 3 and hub 6 in a direction away from the radial shoulder 2 is prevented by a retainer sleeve 8 on the shaft between the outer end of the hub 6 and a bearing unit 9 likewise mounted on the said shaft and maintained against axial displacement in the motor frame by means not here shown.

The resistance end bell 5 flares outwardly in a direction away from the laminated rotor 3 until, at its free end, said bell is of greater diameter than the rotor 3. At said free end the resistance end bell 5 is formed with an annular stiftening flange I0 of substantial width which projects radially outward. This flange acts to eliminate distortion of the bell 5 which might otherwise occur when the rotor is running at high speed, or when the resistance end bell 5 is operated at high heat.

Between the inner end wall I and the annular stiifening flange I0 the resistance end bell 5 is formed with a plurality of circumferentially spaced slots II lcut therethrough and extending in a direction radiating from the apex of said bell. The slots II are of substantial width and are rounded at the ends, as at I2.

A plurality of heavy duty conductor bars I3 of copper or similar high conductivity metal are iitted in circumferentially spaced slots I4 in the laminated rotor 3 adjacent its periphery; the slots running parallel to the shaft axis. The conductor bars I3 are in pairs and each pair projects longitudinally from the laminated rotor 3 toward and through one of the slots II. At the end, adjacent the rounded outer end I2 of the corresponding slot I I, each pair of conductor bars I3 is closed, in electrical relation, by a U-shaped end I5. Each pair of conductor bars I3, with its U-shaped end portion I5, may be termed a conductor bar unit, indicated at I 6, and one of which is shown detached in Fig. 3.

The U-shaped end portions I5 of the conductor bar units I6 are bent laterally outward to an incline matching the taper or flare of the resistance end bell 5, and said end portions l5 thus engage the bell 5 in substantially symmetrical or matching relation to the rounded outer ends I2 of the slots II. The U-shaped end portions I5 of the conductor bar units I6 are permanently affixed to the end bell 5 at the outer end portions I2 of the slots II by brazing or the like, as shown at I'I.

At the end of the laminated rotor 3, opposite the end bell 5, the conductor bars I3 project outwardly slightly and are thence bent laterally, as at I8, into engagement with said end of the rotor. This further locks up the assembly against axial separation.

When the above described induction rotor is in use the current induced in the conductor bars I 3 feeds to the resistance end ball 5 causing heating of the latter and from which end bell the heat dissipates rapidly and effectively. This dissipation of the heat is improved by reason of the fact that the end bell 5 is of stainless steel, which also permits said end ball to run at high heat without distortion or scaling.` The character of` stainless steel is such that it is not dama-ged by high heat nor does it gives' oi'un'desirable scaling at such heat, which would otherwise impair proper operation of the motor by deposit of damaging scale therein. l

Further, the resistance end bell is stamped from a single piece of metal and this'facttogeth er with the inclusion of the annular stiiiening" iiange l0 further minimizes distortion or damage due to high heat or high speed. rotation..

As the conductor bars i3 are exposed outwardly and inwardly of the end bell 5, a fan eiect is accomplished circulating'air throu-gh the slots Il and about the end bell *5,* upon operation of the motor,-to assist in the dissipation of the heat. Air circulation through the rotor unit, is further enhanced by circumferentially spaced cooling bores I9 -which extend through the rotor andv inner end-wall as shown.

From `the foregoing description it willv be readily seen that there has been produced such an induction rotoras substantially fullls the objects of the invention as set forth herein.

While this specication sets forth in detail the present and Vpreferred construction of the induction rotor, still in practice such deviations from such detail may be resorted to as do not form a departure from the spiritvof theV invention, as defined by the appended claims.

' Having thus describedv the invention, the folilowing is claimed as new and useful and upon which Letters Patent isfdesired:

1. An induction rotor unit comprising a rotor including circumferentiallyspaced conductor bars extending lengthwise to and beyond one end of the rotor, a resistance end bell supported adjacent said one end of the rotor concentric to the rotor axis, the extended conductor bars being electrically connected to said resistance' end bell, and means mounting-the' rotor and end bell for rotation in unitary relation; said means including a hub on the end bell engaging said one end of the rotor, a shaft on which the rotor and hub are secured against relative rotation, an abutment on the shaft engaged by the opposite end ofthe rotor, an axially xed bearing unit on the shaft beyond the hub, and a sleeve on the shaftengaged between the hub and bearing unit;

2. An induction rotorv unit comprising a rotor includingl circumferentially spaced conductor bars extending lengthwise to and beyond one end of the rotor, a resistance end bell supported adjacent said one endV ofthe rotor concentric to the rotor axis, the extended conductor bars' being electrically connected to said resistance end bell, and means mounting the rotor and' endbell for rotation in unitary relation; the end bell flaring outwardly in a direction` opposite the rotor` and havinga plurality of circumferentially spaced slots therein, the conductor bars being arranged in pairs corresponding to and projecting` through theslots, each pair includinga continuous outer end portion electrically connected tothe endlbell.

3. An. induction rotor unit comprising a rotor including circumferentially spaced conductor bars extending lengthwise to and beyond one end of the rotor, a resistance end bell supported adjacent said one end of the'rotor concentric to the rotor axis, the extended conductor bars being electrically connected to saidY resistance end bell, and means mounting the' rotor and end ball for rtation in unitary relation; the endY bell flaring outwardly in a' direction opposite the rotor and having a plurality of crcumferentially spaced slots therein, the conductor. barsbeing arranged v'in pairs corresponding to and projecting through the slots, each pair including a continuous outer end portion electrically connected to the end bell, the slots radiating from the apex of the end bell vand being elongated.

4. A rotor unit as in claim 2 in which the continuous end portionof each pair of conductor bars is generally U-shaped, and inclined in generally matching relation to the flare of the end bell.

5; An induction rotor unit comprising a rotor including circumferentially spaced conductor bars extending lengthwise to and beyond one end of the rotor, a resistance end bell supported adjacent said one end of the rotor concentric to the rotor axis, the end bell being of lesser diameter at its inner end than the diameter of the adjacent end of the rotor and thence ilaring'outwardly in a direction opposite said rotor, there being circumferentially spaced slots inthe end bell, the extended conductor'bars being disposed in pairs corresponding to and projecting through the slots, said pairs having continuous outer end portions connected to the end bell, and means mounting the rotor and end bell for rotation in unitary relation. y

6. An induction rotorA unit comprising a rotor including circumferentially spacedl conductor bars extending lengthwise to and beyond one end of the rotor, av resistance end bell supported adjacent said one end of the rotor concentric to the rotor axis, the end bell being of lesser diameter at its'v inner end than the diameter ofthe adjacent end of the rotor and thence flaringoutwardly in a direction opposite said rotor, there being circumferentially spaced slots in the end bell, thel extended conductor bars being disposed in pairs corresponding to and projecting through the slots, said pairs having continuousv outer end portions connected to the end bell, and means mounting the rotor and end bell for rotation in unitary relation; thek end bell having an annular, radially outwardly projecting ilange on its free end.

'7. An induction rotor unit comprising' a'rotor which includes oircumierentially spaced conductor bars, an end bell, such end bell having a relatively at base disposed adjacent one end of the rotor and mounted for rotation with the rotor', the body` of theY bell flaring outwardly from the base,`said conductor bars projecting a distance beyond the end of the rotor adjacent which the bell is disposed, the outer ends of the bars being attached to the bell.

8.v An inductor rotor unit comprisingr a rotor which includes circumferentially spaced conduce tor bars, an endbell, such end bell having a relatively flat base disposed adjacent one. end of the rotor and mounted for rotation with the rotor, the body of the bell aring outwardly from the base, said conductor bars projecting a distance beyond; the end of the rotor. adjacent which the bell is disposed, the projecting ends of theA bars extending through the Haring body of thebell; and the outer ends of the bars being attached to the body. of the bell.

9. An induction rotor` unit comprising a rotor including circurnferentiallyA spaced conductor bars extending lengthwise to points beyond one end of said rotor, and an end bellV ofA high resistance, the closed end of the bell lying adjacent the rotor andv the wall of the bell flaring outwardly in a direction away from' the rotor, the outer ends of the bars being connected with the 5 walls of said end bell at a point intermediate the ends of such end bell.

10. A rotor unit as in claim 9 in which the end bell consists of stainless steel.

ROBERT G. LE TOURNEAU.

REFERENCES CTED The following references are of record in the le of this patent:

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